New Lumatek ballast issue

[finrod2]

Bought replacement lumatec 250-400 adjustable ballast for my 250w hqi pfo fixture. The ballast turns the lamp on for an hour or so then turns off and I can't restart. I have an identical Lumatek ballast already powering another fixture. Is the ballast doing something to the lamp? Thanks for your help.

[moondoggy4]

Could you switch the ballast to rule out one of the variables?

[finrod2]

I figured it out, there was a bad contact on the fixture and the lamp slipped enough to lose contact. Thanks for your reply.